One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,8)(4,7)(5,6)(9,10)(11,14)(12,13)(15,16)(17,18,20,22)(19,23,24,21)(27,33)(28,35)(30,36)(31,38)(1,3,6,4)(2,7,5,8)(10,12)(11,15)(19,24)(21,23)(27,33)(30,36)(34,39)(37,40)(3,4)(7,8)(9,10,13,12)(11,14,15,16)(17,19,20,24)(18,21,22,23)(25,26,29,32)(27,30,33,36)(28,31,35,38)(34,37,39,40)(1,4,6,3)(2,7,5,8)(9,11,13,15)(10,14,12,16)(17,18)(19,23)(20,22)(21,24)(25,27)(26,30)(28,34)(29,33)(31,37)(32,36)(35,39)(38,40)(1,5,6,2)(3,7,4,8)(9,12,13,10)(11,16,15,14)(25,28)(26,31)(27,34)(29,35)(30,37)(32,38)(33,39)(36,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.